Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad Pharm. D II Year PHARMACOLOGY-I Previous Question Paper (February - 2023 - R08)
Answer any five questions
All questions carry equal marks
Main
Define bioavailability. Classify various routes of drug administration and mention their merits and demerits? Write a note on scope of pharmacology.
Answer
Bioavailability is the fraction of an administered dose of an unchanged drug that reaches the systemic circulation. It represents both the rate and extent of drug absorption.
Routes of drug administration are broadly classified into enteral (via the gastrointestinal tract) and parenteral (bypassing the GI tract) routes.
1. Enteral Routes:
- Oral: Most common, safe, and economical. Merits: Convenient, non-invasive. Demerits: Slow onset, first-pass metabolism, potential gastric irritation.
- Sublingual/Buccal: Drug placed under the tongue or in the cheek. Merits: Rapid absorption, bypasses first-pass metabolism. Demerits: Limited to lipid-soluble drugs, unpleasant taste.
- Rectal: Used when oral is not possible. Merits: Useful in vomiting or unconscious patients, partial bypass of first-pass metabolism. Demerits: Inconvenient, erratic absorption.
2. Parenteral Routes:
- Intravenous (IV): Direct injection into a vein. Merits: Immediate effect, 100% bioavailability, suitable for large volumes. Demerits: Irreversible, risk of infection or embolism.
- Intramuscular (IM): Injection into skeletal muscle. Merits: Faster than oral, suitable for moderate volumes. Demerits: Painful, risk of nerve damage.
- Subcutaneous (SC): Injection into subcutaneous tissue. Merits: Suitable for self-administration (e.g., insulin). Demerits: Slow absorption, limited volume.
- Inhalation: Gases or aerosols. Merits: Rapid absorption due to large surface area of lungs. Demerits: Requires specialized equipment.
Scope of Pharmacology:
Pharmacology is the study of drugs and their interactions with living systems. Its scope includes:
- Pharmacokinetics: Study of what the body does to the drug (Absorption, Distribution, Metabolism, Excretion).
- Pharmacodynamics: Study of what the drug does to the body (Mechanism of action, therapeutic effects).
- Pharmacotherapeutics: Application of drugs for the prevention, diagnosis, and treatment of diseases.
- Clinical Pharmacology: Evaluation of drug efficacy and safety in humans.
- Toxicology: Study of the adverse effects of chemicals and drugs on biological systems.
- Pharmacovigilance: Monitoring and preventing adverse drug reactions to ensure long-term safety.
Describe the pharmacology of the following:
Anticholinergic agents
Answer
Anticholinergic agents (muscarinic receptor antagonists) competitively block the action of acetylcholine at postganglionic parasympathetic nerve endings. The prototype is Atropine.
Mechanism of action: They bind to muscarinic receptors (M1-M5) without activating them, preventing acetylcholine from binding. Pharmacological effects include:
- CNS: At low doses, mild stimulation; at high doses, confusion and hallucinations.
- Eye: Mydriasis (pupil dilation), cycloplegia (loss of accommodation), and increased intraocular pressure.
- Cardiovascular: Tachycardia due to blockade of M2 receptors on the SA node.
- Respiratory: Bronchodilation and decreased bronchial secretions.
- Gastrointestinal: Reduced motility and secretions (antispasmodic effect).
- Glandular: Inhibition of salivary, sweat, and lacrimal secretions.
Clinical uses include pre-anesthetic medication, treatment of bradycardia, organophosphate poisoning, and COPD (e.g., Ipratropium).
Antiadrenergic agents
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Define arrhythmias. Classify antiarrhythmic agents and describe their pharmacology. Write a note on drugs used in the treatment of Congestive Heart Failure.
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Describe the pharmacology of the following:
Antihypertensives
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Antihyperlipidemic agents
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Classify NSAIDs. Write their mechanisms of action, adverse effects and therapeutic uses. Write a note of sedatives.
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Describe the pharmacology of the following:
Expectorants
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Nasal decongestants
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Bronchodilators
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Describe the pharmacology of thyroid hormone and Insulin. Write a note on oral contraceptives.
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Classify Antihistaminics and mention their therapeutic uses. Write a note on anti-serotonin agents.
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